This invention relates generally to reaming systems and, more particularly, to an expandable reaming system for reaming an acetabulum in preparation for implanting a prosthetic component, such as an acetabular cup or socket.
Acetabular hip surgery involves reforming the normal hip socket, or acetabulum, so that a proper bearing surface for the ball of the femur is established and which will support normal motion of the leg. The acetabulum needs to be shaped so that it can receive a metallic or plastic artificial socket. To ensure a proper fit of the artificial socket, deteriorated or diseased bone is cut away until healthy bone becomes visible. Typically, reamer heads of increasingly larger size are required as bone is cut away and the socket is enlarged. Each time a larger reamer head is needed, the reaming system must be removed from the patient's acetabulum, the reamer head is removed from the drive shaft of the surgical drill, and the next larger reamer head is attached thereto. This sequence may be repeated several times until the acetabulum is completely prepared to receive an acetabular prosthetic implant.
Several types of acetabular reamer heads are known in the art. Further, a surgical expansive reamer for hip sockets is taught in U.S. Pat. No. 3,702,611. Having to swap reamer heads multiple times during a hip surgery, as discussed above, is inconvenient, inefficient, and may even lead to surgical errors in that the angle of acetabular penetration cannot be accurately preserved during reamer head substitutions. Further, the '611 reamer is also inefficient in that it requires the acetabulum to be prepared with another instrument prior to its use and does not include a satisfactory mechanism for accurate incremental expansion of the reamer.
Therefore, it is desirable to have a reaming system which can be used to prepare an acetabulum to receive an artificial socket without having to substitute one reamer head for another. It is further desirable to have a reaming system having a reamer head which is manually expandable to a plurality of desired sizes.